This invention relates to a flotation apparatus for removing dirt particles and scum from a suspension. More particularly, this invention relates to a flotation apparatus comprising an elongate tank which has successive compartments arranged in the longitudinal direction of the tank to form individual flotation cells, and to which a suspension is supplied which is mixed with air via at least one injector per cell.
An apparatus of this general type is described in U.S. Pat. No. 4,220,612. In this prior art flotation apparatus, the partitions are extended far above the level of the suspension and the injectors are connected to the individual compartments on the outlet side only. Inside the flotation tank, the flow of the suspension proceeds from compartment to compartment through apertures located in the base of the partitions. The suspension is partially removed at the outlet end and is then returned to the individual injectors. The flow of suspension in this prior art apparatus is subject to very unfavorable conditions as regards the elimination of gas bubbles to which the particles of dirt which are present in the suspension have become attached. Each compartment, therefore, needs at least one scum paddle and its own scum removal trough for the removal of scum. Consequently, such prior art apparatus is relatively costly while retaining the disadvantage of unfavorable flotation conditions.